Bluegill is an important freshwater species valued both for sports fishing and as a food fish in Northern America. The interest for growing bluegills both regionally and globally is increasing due to its favorable traits for aquaculture production. Additionally, Bluegill holds ecological and cultural importance for tribal communities in the upper Midwest region. Yet, limited research exists on strategies to improve sustainable aquaculture practices to improve growth and health in Bluegill production. This study represents the first research initiative that is being conducted at the College of Menominee Nation, to investigate the effects of probiotic addition on Bluegill growth performance and microbiome manipulation.
Probiotics are live microorganisms that provide beneficial effects on the host species. Lactic acid bacteria and Bacillus spp. are among the most widely used probiotic strains in the aquaculture industry. These microorganisms interact with fish gut microbiota and contribute to many health and growth promoting functions.
The present research trial is being conducted at College of Menominee Nation, Aquaculture high tunnel. In this recirculating aquaculture system, nine cylindrical tanks of 265 L were stocked with 30 juvenile Bluegills (39.9 ± 5.3g) in each tank. This study evaluates 2 probiotic strains with three distinct diets in total, each containing three replicates: a commercial diet with 40% crude protein and 10% lipid (Zeigler Bros. Inc., Gardners, PA) as the control and commercial diet top coated with either YHH-B13 (Bacillus subtilis) or YHH-B16 (Lactobacillus plantarum) (Creative Biogene, Shirley, NY). The commercial stock of both YHH-B13 and B16 (1 x 108 CFU g-1) were suspended in distilled water according to the manufacturer’s specifications and sprayed onto feed for a final concentration of 1.0 x 105 CFU g-1. Bluegills are being fed 2% of their body weight twice a day for 12 weeks. Fish are weighed every two weeks to adjust the feed rations. Water quality parameters are checked regularly to maintain the optimum water quality conditions for the Bluegills. At the end of the feeding trial period fish will be counted and weighed in each tank to calculate the growth parameters. Fecal samples from 3 fish per tank will also be extracted for gut microbiome analysis.
The trial is currently at 8 weeks and all treatment effects on growth parameters, survival and fish gut microbiome will be analyzed upon completion of the 12-week feeding period. This study will generate foundational knowledge on how probiotic addition will influence Bluegill growth and microbiome. These results will also support tribal and local communities by strengthening food security and advancing culturally relevant research at College of Menominee Nation.